I haven't seen many comments on the latest upgrade for the SD1. Is anyone out there using it? What are the changes? Are there problems? I'm currently on 3B but would like to get up to date if I can do so without creating any problems. Will someone please describe the enhancements this would add to my current set up. I love this keyboard. With few exceptions, it has the best, most realistic sounds of any keyboard. I would like to see some rhythm enhancements and just a couple of instrumental sound improvements.